youre probably right. my noise level is pretty much where i want it to be anyways. I wouldnt mind some more power, but maybe with a tune ill be happier.. but i know what youre talking about. my friend's bike has no cats and its pretty bad, im sure a car engine would be even worse.

The benefit of keeping the oem design and deleting cats is the sound increase is almost zero but gains are there so nothing to worry about with that. I can barely hear my exhaust with all oem system but no cats. I was thinking of deleting my resonator.

My non stock system with larger piping, no cats and no res was waaaaay too loud though. That was mainly because of the pipe sizing.

Quote:

Originally Posted by Route 16

Any type brand of cats will do instead of OEM ones?

I am actually thinking of using another set of stock mid pipes with some magnaflow high flow cats just so I don't have the smell.

Ok. So I figured I would just post the crappy cell phone pic of the dyno results and a short video. Specs were as such:

Dynocom - bolted into wheel hubs

Stock Run on Chevron 94 - No ethanol

Header run - 92 grade containing ethanol from no name gas station

There was a ping in the run that didn't affect HP but threw max tq off

Despite the ping max tq was around 174 ft lbs. So around 20lbs gain

One of the runs showed 12 whp max gain - not super important because its the delta that matters

Greatest TQ gains are in the 2.5 to 3.5 rpm range

Video briefly shows flatter curves without ping

Best pulls were 5th and 4th base and headers respectively

Avg tq gains throughout the band were 14lbs

Avg hp gains were about 9.X

I highlighted the graph in pen because lines were faint

6 pulls each time - best runs were taken, although the pull before the one on the graph had higher MAX HP and no ping if I remember correctly. I should of had him put that one on. I was in a daze when this went down because we had a baby the night before and I barely had any sleep. Yes. I dyno'd the day after having a child. Don't judge me.

why the curves look like hand drawn? Shouldn't them be printed out by computer?

Thanks SDemetris. I have a set for sale in the classifieds. It was the first sample. I could make 100 tomorrow but the interest really seems lacking. I put the sample at a crazy low price too with gaskets. For this price, it has more gains than a tune and is cheaper and easier to install than an IM. Not sure what the deal is.

Obiwanchen bought my sample....is there any interest in more sets? A lot of interest but no one who is solidly committed. It will take a chunky investment for me to get more made. Will need to do around 10-15 sets. What say you oh N52 modders?

Interested, would like to know the price. Plus without a tune, will the mpg still go up? I feel like without the primary cats the a/f ratio will be off and Ill be dumping more fuel causing less mpg than I'm getting now. I plan to keep the stock exhaust for sound reasons so Im wondering if the awful smell will be there with everything stock except the headers. Awesome work by the way, these things look legit.

I'd be very interested in purchasing a set if the price is right- Awesome work.

I am aiming to keep it at $700 and this includes all new main gaskets, which are over $100 from BMW. I could possibly even include gaskets for where the midpipes hook up.

Quote:

Originally Posted by randomquickness

count me in as long as the price is right.

also curious, can the error light be coded out instead of using the dp fix?

Light can be coded out by AA if you get their tune. This is probably the best bet to maximize everything, but gains are instantly noticeable and dyno proven without a tune.

Quote:

Originally Posted by makisupa

Also had the same question, and interested as well.

see above

Quote:

Originally Posted by bmwkyle

Interested, would like to know the price. Plus without a tune, will the mpg still go up? I feel like without the primary cats the a/f ratio will be off and Ill be dumping more fuel causing less mpg than I'm getting now. I plan to keep the stock exhaust for sound reasons so Im wondering if the awful smell will be there with everything stock except the headers. Awesome work by the way, these things look legit.

Price I am aiming for is above. I notice MPG boost immediately. It was insane how much better it was. You will not notice the smell difference or a sound difference with the secondaries in place. It was only noticeable for me when I took out secondaries.

Thanks for the info OP! I'll be paying attention to this thread hoping more will want to jump on board so you can get some of these produced!

well, as you could imagine, there is quite some money involved in making 10 to 15 sets. I guess I will make a decision in a few weeks.

Quote:

Originally Posted by bmwkyle

Yes, thanks for the information on this. I would like to hear from the person who bought your mock ups. See what he thinks of them. These looks very promising though.

The ones obiwanchen bought were built from the same jig as the ones on my car. They should fit perfect. He installs next week though and he will be FBO xdrive 328i. I hope he dynos cuz im itching to see all the gains. With the recent sale from active, the cost of my headers and if someone finds
a inexpensive 3 stage IM, it is becoming a lot cheaper to spruce these cars up.

What is the size on the outlet piping? Might be a noob question but I wonder if two high flow cats can be welded onto these headers. Like take a piece of pipe out and replace with high flow cats. I don't plan on getting a tune anytime soon (my last modified) so I would think the a/f ratio to good. Without those cats and o2 sensors in line, I feel like the ratio will be off. Am I wrong here or no?

What is the size on the outlet piping? Might be a noob question but I wonder if two high flow cats can be welded onto these headers. Like take a piece of pipe out and replace with high flow cats. I don't plan on getting a tune anytime soon (my last modified) so I would think the a/f ratio to good. Without those cats and o2 sensors in line, I feel like the ratio will be off. Am I wrong here or no?

To be honest, I don't think the gains from HFC's alone would be worthwhile, given the cost of doing so. Maybe you could find cheap stock manifolds and do that. It would be better than buying mine then having cats put in. I don't see a big market in that for me to rebuild a jig based off a set with high flow cats. On the A/F topic. I can conclusively say without looking at ratios before and after. My experience is that my mpg improved greatly.

Quote:

Originally Posted by randomquickness

I'm willing to pay a deposit if that helps...I assume others who are serious would be willing to do the same. Let's get these made!

If I can get just two people to commit 50% down I am more than willing to put up the rest for 10-15 sets.

Obiwanchen bought my sample....is there any interest in more sets? A lot of interest but no one who is solidly committed. It will take a chunky investment for me to get more made. Will need to do around 10-15 sets. What say you oh N52 modders?

What is the price? I can commit if its within the range I'm expecting. 50% papal'd would be fine.

Its for Catless manifold correct?

__________________

Quote:

Originally Posted by Built My Way

Rule #1 when you own "The Ultimate Driving Machine". Always have $$$ in "The Automatic Teller Machine"